// 
// Copyright (c) 2006-2009 Ben Motmans
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
// Author(s):
//    Ben Motmans <ben.motmans@gmail.com>
//

using System;
using System.IO;
using System.Collections.Generic;
using System.Security.Cryptography;

namespace Anculus.Core
{
	public static class Rsa
	{
		public static ByteBuffer Encrypt (ByteBuffer data, RsaKey key)
		{
			if (data == null)
				throw new ArgumentNullException ("data");
			if (key == null)
				throw new ArgumentNullException ("key");
			
			RSACryptoServiceProvider rsa = key.CryptoProvider;
			return new ByteBuffer (rsa.Encrypt (data.Raw, true));
		}
		
		public static ByteBuffer Decrypt (ByteBuffer data, RsaKey key)
		{
			if (data == null)
				throw new ArgumentNullException ("data");
			if (key == null)
				throw new ArgumentNullException ("key");
			
			RSACryptoServiceProvider rsa = key.CryptoProvider;
			return new ByteBuffer (rsa.Decrypt (data.Raw, true));
		}
		
		public static ByteBuffer SignHash (ByteBuffer hash, RsaKey key)
		{
			if (hash == null)
				throw new ArgumentNullException ("hash");
			if (key == null)
				throw new ArgumentNullException ("key");
			
			RSACryptoServiceProvider rsa = key.CryptoProvider;
			return rsa.SignHash (hash.Raw, CryptoConfig.MapNameToOID("SHA1"));
		}
		
		public static bool VerifyHash (ByteBuffer hash, ByteBuffer signature, RsaKey key)
		{
			if (hash == null)
				throw new ArgumentNullException ("hash");
			if (key == null)
				throw new ArgumentNullException ("key");
			
			RSACryptoServiceProvider rsa = key.CryptoProvider;
			return rsa.VerifyHash (hash.Raw, CryptoConfig.MapNameToOID("SHA1"), signature.Raw);
		}
		
		public static ByteBuffer SignData (ByteBuffer data, RsaKey key)
		{
			//no need to check args

			ByteBuffer dataHash = Hash.Sha1 (data);
			return SignHash (dataHash, key);
		}
		
		public static bool VerifyData (ByteBuffer data, ByteBuffer signature, RsaKey key)
		{
			//no need to check args
			
			ByteBuffer dataHash = Hash.Sha1 (data);
			return VerifyHash (dataHash, signature, key);
		}
		
		public static ByteBuffer SignFile (string fileName, RsaKey key)
		{
			//no need to check args
			
			ByteBuffer dataHash = Hash.Sha1File (fileName);
			return SignHash (dataHash, key);
		}
		
		public static bool VerifyData (string fileName, ByteBuffer signature, RsaKey key)
		{
			//no need to check args
			
			ByteBuffer dataHash = Hash.Sha1File (fileName);
			return VerifyHash (dataHash, signature, key);
		}
	}
}